From the other side of the consultation, briefly. Start from the measurement rather than the conclusion. Almost every disagreement here turns out to be two people measuring different things and comparing the numbers anyway.

The figures, for anyone assembling their own picture. Say what you would expect to see if you were wrong, before you look. It is a small discipline and it changes what you notice.

Following on from FDA_TrackerJim — and this may be the naive question:

Whether a purity figure and a content figure can disagree without one of them being wrong?

Dr.PeteFamMed said:

Say what you would expect to see if you were wrong, before you look.

I read this differently from Dr.PeteFamMed, on substance rather than tone. The objection nobody has made: this only works if the measurement is doing what we assume it is doing, and that assumption has not been tested here.

Correct me if the detail matters more than I have assumed.

Moderator note: the sourcing question belongs in the vendor section and has been split out. No action needed from anybody.